Thiopurines are an established treatment for inflammatory bowel disease (IBD) patients. They are used to reduce inflammation and provide symptom relief. Thiopurine immunosuppressive drugs have now been reported to increase the risk of acute myelod leukemia and myelodysplastic syndrome, a rare bone marrow disorder, seven-fold among IBD patients. These data were recently reported in a new study published in the medical journal Clinical Gastroenterology and Hepatology.

Common thipurines include azathioprine, 6-mercaptopurine and 6-thioguanin. The researchers conducted a prospective observational study to determine the trends of IBD patients exposed to thiopurines. French researchers studied 19,486 patients enrolled a study between May 2004 and June 2005. After three years of follow up, five patients were diagnosed with myeloid disorders and 4 of these patients had been previously exposed to thiopurines. Patients who were not receiving thiopurines during the study and those who never received these drugs were not found to have an increased risk of myeloid disorders.

IBD can negatively impact an individual’s life and result by limiting certain activities and be a financial burden. Treatments for IBD have expanded recently and patients have more choices. In order to make appropriate, informed decisions about the use of thiopurines as well as other medications, patients and their doctors need to be well-educated about the risks and benefits of any treatment

These findings provide evidence of a connection between thiopurines and myeloid disorders in IBD patients. The absolute risk to an individual patient however is relatively modest: only 1 in 10,000. Physicians and their patients will need to balance this risk against the known benefits of thiopurines as well as other treatment choices in their overall management of IBD.